fix(apache#23176): adding URL decoding to SQLAlchemy URI (apache#23421)

Co-authored-by: Evan Rusackas <evan@preset.io>

superset/migrations/env.py

@@ -15,6 +15,7 @@
 # specific language governing permissions and limitations
 # under the License.
 import logging
+import urllib.parse
 from logging.config import fileConfig
 from typing import List
 
@@ -42,7 +43,8 @@
         "SQLite Database support for metadata databases will \
         be removed in a future version of Superset."
     )
-config.set_main_option("sqlalchemy.url", DATABASE_URI)
+decoded_uri = urllib.parse.unquote(DATABASE_URI)
+config.set_main_option("sqlalchemy.url", decoded_uri)
 target_metadata = Base.metadata  # pylint: disable=no-member